Help me debug my BMP

[soggybag]

I built a BMP a few months ago and I still can't get it to work. I was fed up with it for a while so I put it aside. But I've decided I must get this thing working or ahng up my soldering iron!

I traced everything with the audio probe and everything seems to work up to collector of Q3. I get a low output farty sound. Q4 shows

E = .15V
B = .79V
C = .30V

Give me some suggestions. I have been looking very closely and it seems like everything is wired correctly.

[the_random_hero]

What version/schematic are you working off? Without being too familiar with that circuit, I can tell you now that your voltages are the cause of the problem. Check any resistors feeding the transistor or any cold solder joints.

[R.G.]

What to do when it doesn't work...

[frankclarke]

Everything can't be wired correctly, so rebuild the Q4 stage and what R.G. said.

[soggybag]

So those values look wrong. Is the bias off? I'll check that last stage again.

I'm building the standard BMP:
http://members.fortunecity.com/uzzfay/bigmuff/bmsch.gif

[soggybag]

So looking through the Debug FAQ. I find

Remember that for an NPN silicon transistor to be working as a linear amplifier, it MUST have its base higher than its emitter by about one silicon diode drop, 0.5 to 0.7V, and the collector must be higher than either base or collector. The collector-to-emitter voltage is the size of the negative half signal swing, and the power-to-collector voltage is the size of the positive half signal swing.

I assume "...the collector must be higher than either base or collector." means the collector must be higher than the base or the emitter

Looking at what I have it seems the base and emitter look good. But my collector is too low. It should be more in the neighborhood of 3V?

Let me take another look and see what I can find.